There are dozens of dialects spoken in Japan. Among them are Kansai-ben, Tohoku-ben, and Kanto-ben (Tokyo and surrounding areas). Dialects are generally mutually intelligible, although extremely geographically separated dialects such as the Tōhoku and Kyūshū variants are not. Dialects typically differ in terms of pitch accent, morphology of the verb and adjectives, particle usage, vocabulary and in some cases pronunciation.

The Ryukyuan languages used in and around Okinawa are related to Japanese, but the two are mutually unintelligible. Due to the close relationship they are still sometimes considered only dialects of Japanese.

Optionally, an initial consonant, chosen from the 15 consonant phonemes not including ʔ and ɴ,

A vowel, which may be short or long, and

Optionally, either ɴ or ʔ, the glottal stop. (Note that the latter can only occur preceding subsequent syllables in the same word beginning with the k, s, t, and p phoneme. This is often referred to as a doubled consonant.)

Japanese vowels are pure sounds like their Italian counterparts. The only unusual vowel is the high back vowel, which is indicated as /u/ in the diagram. This vowel is often described as unrounded, but is actually pronounced with "compressed lips", which is a different articulatory gesture from either rounded or unrounded lips: it is unrounded, but without spreading. The "u=" to the right of the diagram are possible narrow transcriptions using IPA, as suggested by the Handbook of the International Phonetic Association.

In some English dialects, Japanese vowels can be approximated as follows:

The consonant /ɺ/ is tricky for English speakers. To an English speaker's ears, its pronunciation lies somewhere between an "r" /ɹ/, an "l", and a "d". The sound may be made by lightly placing the tongue on the back of the upper set of teeth and producing the sound /l/. Some have noted that the pronunciation is close to the Spanish "r".

/N/ becomes [n] before coronals /d/ and /t/ (like English "and" and "ant");

/N/ becomes palatal before /j/ and /i/ (like English "news");

/N/ becomes velar before /k/ and /g/ (like English "sunk" and "sung");

/N/ becomes a nasalized vowel before a vowel, approximant, /h/, or /s/.

/s/ and /z/ become alveolo-palatal [ɕ] and [dʑ] before /i/, /j/;

/t/ and /d/ respectively become [ts] and [z] before /u/, and [tɕ], [dʑ] before /i/, /j/;

/ʔ/ assimilates to the following consonant, thereby forming a geminate;

/h/ becomes bilabial [ɸ] before /u/ (like English "f" but considerably softer: it is not made by pressing the teeth against the lips; rather, it is made by closing one's lips slightly and lightly blowing.);

/i/ and /u/ tend to become devoiced between unvoiced consonants or at the end of sentences, except when they are in accented or lengthened syllables. Often, preceding fricatives will replace the vowel altogether.

In English, stresseded syllables in a word are pronounced louder and longer. In Japanese, all moras are pronounced with equal length and loudness. Syllables can consist of one, two, or three moras, depending on the presence or absence of a long vowel and/or a doubled consonant (really glottal stops), each of which adds one mora to the syllable length. Japanese is therefore said to be a mora-timed language.

In Japanese, a stressed syllable is merely pronounced at a higher pitch. This is part of the Japanese intonation pattern.

Japanese does have a distinct intonation pattern. This pattern can be heard not only in individual words, but also in whole sentences. Intonation is produced by a rise and fall in pitch over certain syllables. In the case of questions, the Japanese intonation patterns bear little resemblance to the English ones. This is a large source of confusion for westerners.

1. The basic sentence structure of a Japanese sentence is TOPIC-COMMENT.

For example:

Kochira wa, Sangaa san desu.

Kochira is the topic of the sentence, indicated by the particle wa. This means "as for this person."

The verb is desu ("be").

Sangaa san desu is the comment.

Therefore, this loosely translates to:

"As for this person, (it) is Mr. Sanger."

Therefore Japanese, like Chinese, is often called a topic-prominent language, which means it marks topic separately from subject, and the two do not always coincide.

2. Japanese nouns in general have neither number nor gender. Thus hon (book) can be used for the singular or plural. However, in the case of a small number of native words (of proto-Japanese rather than Chinese origin) plurality may be indicated by reduplication. For example, hito means "person" whilst hitobito means "people"; ware means "I" whilst wareware means "we". Sometimes suffixes may also indicate plurality. Examples include the suffixes tachi and ra: watashi, meaning "I", becomes watashitachi, meaning "we", and kare (him) becomes karera (them).

3. With some exceptions Japanese is SOV (with the verb at the end of the sentence.) It also has the prepositional order of Time Manner Place which is opposite to English's prepositional order.

4. Verbs are conjugated to show tenses, of which there are two: the present (sometimes, because the same form is used for both the present and future, called the "non-past") and the past. The present tense (or imperfect tense) in Japanese serves the function of the simple present and the future tense, while the past tense (or perfect tense) in Japanese serves the function of the simple past tense. The distinction is between actions which are completed (perfect) or are not yet completed (imperfect). The present perfect, present continuous, present perfect continuous, future perfect, future continuous, and future perfect continuous are usually expressed as a gerund (-te form) plus the auxiliary form imasu/iru. Similarly, the past perfect, past continuous, and past perfect continuous are usually expressed with the gerund plus the past tense of imasu/iru. For some verbs, that represent an ongoing process, the -te iru form regularly indicates a continuous (or progressive) tense. For others, that represent a change of state, the -te iru form regularly indicates a perfect tense. For example, kite imasu regularly means "I have come", and not "I am coming", but tabete imasu regularly means "I am eating", and not "I have eaten". Note that in this form the initial i of imasu/iru is often not voiced, especially in casual speech and the speech of young people. The exact meaning is determined from the context, as Japanese tenses do not always map one-to-one to English tenses. In addition, Japanese verbs are also conjugated to show various moods.

5. Adjectives are inflected to show the present, past, affirmative and negative.

6. The grammatical function of nouns like possession, direct object, indirect object etc. are indicated by postposition particles, like ha and no above. Particles play an extremely important function in Japanese.

7. Japanese has many ways to express different levels of politeness, including special verbs, verbs indicating relative status, use of different nouns, etc., as was shown above.

8. The verb desu/da is not a copula in the western sense of the verb "to be". In the sentences above, it has played the copulative function of equality, that is: A = B. However a separate function of "to be" is to indicate existence, for which the verbs arimasu/aru and imasu/iru are used for inanimate and animate things respectively.

9. Derived forms of words occur often in Japanese. Nouns can be made into verbs, adjectives into nouns, gerunds, and other forms, and so on. Verbs, in addition to other derived forms, have one (the -tai form) which is an adjective meaning "want to do X"; e.g., tabetai desu means "I want to eat".

10. Instead of having Pronouns, Japanese often simply remove any obvious nouns. for example, instead of someone saying "watashi wa byuoku desu" (I am sick), one would say "byuoku desu" (am sick). This is a very simple example, and can be more complex. Whole sentences can be made of verbs alone.

Since most relationships are not equal in Japanese society, one person typically has a higher position. This position is determined by a variety of factors including job, age, experience, or even psychological state (e.g., a person asking a favor tends to do so politely). The person in the lower position is expected to use a polite form of speech, whereas the other might use a more plain form. Strangers will also speak to each other politely. Interestingly, Japanese children rarely use polite speech until their teenage years, at which point they are expected to begin speaking in a more adult manner.

The plain form in Japanese is recognized by the shorter, so-called dictionary (jisho) form of verbs, and the da form of the copula. In the teinei level, verbs end with the helping verb -masu, and the copula desu is used. The advanced polite form, keigo, actually consists of two kinds of politeness: honorific language (sonkeigo) and humble (kenjōgo) language. Whereas teineigo is an inflectional system, keigo often employs many special (often irregular) honorific and humble verb forms.

The difference between honorific and humble speech is particularly pronounced in the Japanese language. Humble language is used to talk about oneself or one's own group (company, family) whilst honorific language is mostly used when describing the interlocutor and his group. For example, the -san suffix ("Mr.", "Mrs." or "Ms.") is an example of honorific language. It should not be used to talk about oneself. Nor should it be employed when talking about someone from one's own company to an external person, since the company is the speaker's "group".

Most nouns in the Japanese language may be made honorific by the addition of お o- or ご go-; as a prefix. o- is generally used for words of native Japanese origin, whereas go- is affixed to words of Chinese derivation. In some cases, the prefix has become a fixed part of the word and is included even in non-honorific speech, such as gohan, or rice. Such a construction usually indicates deference to either the item's owner or to the object itself. For example, the word tomodachi ("friend"), would become o-tomodachi when referring to the friend of someone of higher status. On the other hand, a female speaker may sometimes refer to mizu (water) as o-mizu merely to show her cultural refinement, compared to more abrupt male speech patterns.

Many researchers report that since the 1990s, the use of polite forms has become rarer, particularly among the young, who employ politeness to indicate a lack of familiarity. That is, they use polite forms for new acquaintances, but as a relationship becomes more intimate, they speak more frankly. This often occurs regardless of age, social class, or gender.

"Radcliffe, Olympic marathon contestant, to consider also appearing in the 10,000 m"

For an example of a word (watashi, meaning "I") written in each of the four scripts, see the table below.

Kanji

Hiragana

Katakana

Rōmaji

私

わたし

ワタシ

watashi

Since all Japanese are taught English in middle school and high school, most Japanese can read rōmaji. As a result, the amount of rōmaji in Japanese has increased considerably in recent decades. Japanese popular music lyrics in particular increasingly contain English words and phrases. Foreign loanword (gairaigo 外来語) usage has both proponents and opponents in and out of Japan.

Due to the large number of words and concepts entering Japan from China which had no native equivalent, many kanji words entered Japanese directly, with a pronunciation similar to the original Chinese. This Chinese-derived reading is known as on-yomi 音読み, and this vocabulary as whole is referred to as Sino-Japanese. At the same time, native Japanese already had words corresponding to many borrowed kanji. Authors increasingly used kanji to represent these words. This Japanese-derived reading is known as kun-yomi 訓読み. A kanji may have zero, one or several of each of on-yomi and kun-yomi.

Linguists have sometimes compared Japan's borrowing and adaptation of Chinese words into Japanese as similar to the effect of the Norman conquest of the British Isles had on the English language. Like English, Japanese has many synonyms of differing origin: words from both Chinese and native Japanese. In another similarity, words of Chinese origin often sound more formal or intellectual to a Japanese speaker, just as the latinate words in English often sound to an English speaker.

The arrangement of kana in a more easily memorized and logical order (/a/, /i/, /u/, /e/, /o/), rather than the arrangement based on the traditional iroha poem.

The start of debates which eventually led to a government approved set of kanji for general use. These lists, the tōyō kanji 当用漢字 and jōyō kanji 常用漢字, were officially approved in 1946 and 1981, respectively. Similar lists for kanji used in names were similarly approved (jinmeiyō kanji 人名用漢字). Today, 1,945 kanji characters are taught in the nine years of compulsory education, together with Hiragana and Katakana that represent 46 characters each.

Western influences during the Meiji Era, and continued influences during the American occupation after World War II, also had important effects on the Japanese written language. One effect was on the use of foreign words (gairaigo 外来語) in Japanese, as well as the increased use of rōmaji. Another effect was to change the writing direction of Japanese.

Until the Meiji era, Japanese text was written top to bottom, right to left. The Meiji era saw the first use of horizontally written Japanese. Before World War II, this horizontal text was written from right to left, so as to be consistent with traditional Japanese writing. After the end of World War II, text started to be written from left to right, in the common western style. Both kinds of writing are still in use today. Occasionally, horizontal writing from right to left can still be seen, when the reader is likely to encounter the text in in that direction (as in on the sides of vehicles, where text is often written from the front to the rear on both sides of the vehicle). This can sometimes cause a funny situation. "Kaba", a type of tree was used as a name for a frigate in WW2 but was spelled "Ba""ka", "stupid" on the side of the ship.

When a Japanese reader encounters the different script, he or she can infer what kind of character wrote or is the subject in the sentence. In manga (to a lesser extent, video games), encoding information by script shifts plays a significant role as it enables artists to pack more information in a little space. For example, with the single word watashi in Katakana readers will expect a foreign character to appear next, without even a single drawing of a foreigner beforehand. This could also be used for a dramatic effect coupled with the conjugation of verbs. A female disguised as a male could be written to use Kanji watashi when her secret is kept with the appropriate conjugation of verbs. Then when the secret is revealed, she would be written to use Hiragana watashi without taking off her disguise or any change in the way she is drawn. This technique could be inverted if a male is disguised as a female. With these techniques, even artists with limited drawing skill could represent different characters easily. This technique is used in other forms of literature, with the same or even dramatic effects.